1. Field of the Invention
The present invention relates to a body of a motorcycle, and more particularly to an engine hanger which provides a particularly flexible body.
2. Description of Background Art
Japanese Unexamined Patent Publication No. 11-1192 discloses a vehicle body frame which is constituted such that the vehicle body frame includes a pair of left and right main frames which in the front-back direction above an engine and a cross pipe which connects the main frames by bridging, and an upper engine hanger has one end thereof welded to the center of the cross pipe and the other end extending downwardly to support an upper portion of the engine. In this publication, the front-back direction, the up-down direction and the left-right direction are basically determined using the normal traveling state of a vehicle as the reference.
The vehicle body frame is not only required to simply increase its rigidity but also may be required to have the characteristics which allow the body to flexibly bend at the time of cornering or the like in accordance with specifications. However, in the above-mentioned conventional structure, since the engine also contributes to an increase in the rigidity of the vehicle body frame as a portion of the vehicle body frame, it has been difficult to provide flexibility to the vehicle body frame. Accordingly, it is an object of the present invention to provide the flexibility to the vehicle body frame while ensuring a relatively simple structure.
To solve the above-mentioned problems, a vehicle body frame structure according to the present invention includes a vehicle body frame for mounting an engine by utilizing an engine hanger. The vehicle body frame includes a pair of left and right main frames which extend in the front-back direction above said engine and a cross pipe which connects the main frames by bridging. An arm portion extends from the cross pipe approximately horizontally, and an upper engine hanger which is extended downwardly for supporting an upper portion of the engine is mounted on a tip end side of the arm portion.
According to the present invention, since the arm portion extends from the cross pipe and the upper engine hanger extends downwardly and is supported on the tip end side of the arm portion, this arm portion can be easily deflected at the time of cornering and hence, the flexibility can be given to the vehicle body frame. Further, since the provision is constituted simply by the addition of the arm portion, it becomes possible to provide flexibility to the vehicle body frame with a relatively simple structure.
The upper engine hanger includes an engine-side portion which extends downwardly from the vehicle body frame side and the arm portion includes a remaining portion of the vehicle body frame side which extends in an approximately horizontal direction and is connected to the cross pipe. Further, by adjusting the length of the arm portion, the flexibility can be desirably adjusted.
The upper engine hanger may be formed separately from or integrally with the arm portion. By forming the upper engine hanger separately from the arm portion, the rigidity can be adjusted for each portion. Further, it is expected that the upper engine hanger and the arm portion can be used among machines of different types thus enhancing the generality of the upper engine hanger and the arm portion. Further, by forming the upper engine hanger and the arm portion integrally, the number of parts can be reduced so that it becomes possible to make the structure simpler.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.